Foam-forming composition



' Patented Oct. 22, 1929 UNIT HANS BUBMEISTER, OF BERLIN, GERMANY, ASSIGNOR TO PYRENE-MINIM AX CORPORA- TION, A. CORPORATION OF DELAWARE FOAM-FORMING COMPOSITION No Drawing. Application filed October 21, 1927, Serial No. 229,256, and in Germany April 24 1924.

portions to form foam, preferably, a neu-- tral or slightly acid foam. The use of alu- 10 minum sulphate as an acid-in the combination has certain advantages as forming a'more lasting foam but when it is stored for a long time before actual use in the form of a powder there is a risk that at the time of use the powder will have become somewhat damp or slimy, or that when, in use, the water is added the sulphate will tend to form a slime instead of dissolving quickly and readily in the water. This difficulty is especially found when the foam forming apparatus is of the type in which the water is supplied in a stream engaging a large body of powder.

The present invention makesprovision for combining with the aluminum sulphate another acid which acts as a booster and facilitates the dissolving of the sulphate in water in a way to reduce the risk of ineffective operation due to deterioration of the sulphate. The sulphate is combined with another suitable acid such as tartaric acid, citric acid or oxalic acid, or a mixture of them, with the result that even after long storage under adverse conditions, it will dis solve readily in water and the resulting acid solution may be combined with a suitable alkali to form foam.

The sulphate and other acid or acids may be combined, for example, in the proportion of seventy-five to ninety (75 to 90) parts of sulphate and twenty-five to ten (25 to 10) parts of acid. If all of the foam forming chemicals are to be combined in one powder, such a powder may contain, for example, eight -five (85) parts of aluminum sulphate and fteen (15) parts of tartaric acid, citric acid and oxalic acid, or any of them, together with sufficient sodium carbonate to form a neutral or slightly acid foam. The combined powder will operate effectively even after long storage and when the foam forming apparatus fails to afford the most effective 1. The method of producing foam for fire 7 extinguishing purposes which comprises mamtaining in dry powdered form a mixture of foam form ng chemlcals including alumitate the dissolving in water ofvthe aluminum sulphate, and combining said mixture with water at the time of use to form foam;

2. The method of producing foam for fire extinguishing 'purposes Wl11Ch comprises maintaining in dry powdered form a mixture of foam forming chemicals including 75 to 90 parts of aluminum sulphate and 10 to 25 parts of acid adapted to facilitate the dissolving in water of the aluminum sulphate, and combining said mixture with water at the time of use to form foam.

3. The method of producing foam for fire extinguishing purposes which. comprises maintaining in dry powdered form a mixture of foam forming chemicals including 85 parts of aluminum sulphate and 15 parts of tartaric acid, citric acid and oxalic acid together with an alkali, and combining said mixture with water at the time of use to form foam.

4. The method of producing foam for fire extinguishing purposes which comprises maintaining in dry powdered form a charge of foam forming chemicals including aluminum sulphate and an acid adapted to facilitate the dissolving in water of the aluminum sulphate, and directing a stream of water into said charge.

5. The method of producing foam for fire extinguishing purposes which comprises maintaining in dry powdered form a mixture of foam forming chemicals aluminum sulphate and an acid adapted to facilitate the dissolving in water of the aluminum sulphate togther with an alkali,

including num sulphate and an acid adapted to facili phate together'with an alkali, and directing I and Combining said mixture Water to form foam.

6. The method of producing foam for fire V extinguishing purposes which comprises maintaining in dry powdered form a charge of foam forming chemicals including aluminum sulphate, an acid adapted to facilitate the dissolving in Water of the aluminum sula stream of water into said charge to form foam. i p

7. A charge for fire extinguishing apparatus comprising a mixture of aluminum sulphate and organic acid and an alkali, all in powder form.

8. A charge for fire extinguishing apparatus comprising a dry mixture of foam forming chemicals including to 90 parts of aluminum sulphate, 10m 25 parts of other acid, and an alkali in proportion to form foam when mixed with water.

9. A charge for fire extinguishing apparatus comprising a dry mixture containing approximately parts af aluminum sulphate and 15 parts of other acid.

HANS 'BURMEISTER. 

